Until lately, radiographs have been recorded on X-ray films that have been exposed and subsequently developed. Since X-ray films of this kind have determined standard formats, the sizes of the holders resp. of the clamping portions intended for receiving the X-ray films are standardized too. Up to now, the main problem with regard to such X-ray film holders has been to enable radiographs of the bitewing and of other areas of the teeth with a minimum number of different holders, while the film formats are mostly clamped either transversely or longitudinally.
Recently, a new imaging technique has been developed where digital image sensors are directly connected to a computer by a cable in order to directly display or store the radiographs on the latter.
In contrast to X-ray films, the different digital sensor products have different dimensions with regard to length and width and to thickness. Moreover, sensors of this kind comprise a cable, thereby making the correct positioning of such sensors problematic.